1. Technical Field
The technical field relates to a surgical apparatus, and more particularly to a surgical stapling apparatus that can perform operations such as articulation, tissue clamping, staple forming and/or tissue cutting.
2. Background of Related Art
Surgical stapling instruments are known wherein tissue is first grasped or clamped between opposing jaw structure and then fastened by means of fasteners. In some instruments a knife is provided to cut tissue which has been joined by the fasteners. The fasteners are typically in the form of surgical staples, however, two part polymeric type fasteners are also known.
Instruments for this purpose can include two elongated jaws which are respectively used to capture or clamp tissue. Typically, one of the jaws carries a disposable cartridge wherein a plurality of staples are arranged in at least two lateral rows while the other jaw has an anvil for forming the staple legs as the staples are driven from the cartridge. Generally, the stapling operation is effected by a camming element which travels longitudinally through the cartridge carrying member and acts upon individual staple pushers to sequentially eject the staples from the cartridge. A knife can be positioned in such a manner so as to operate sequentially immediately behind the camming element and laterally positioned between the staple rows to longitudinally cut and/or open the stapled tissue between the rows of staples. Such instruments are disclosed in Bobrov et al. (U.S. Pat. No. 3,079,606) and Green '675 (U.S. Pat. No. 3,490,675).
A later instrument disclosed in U.S. Pat. No. 3,499,591 to Green applies a double row of staples on each side of the incision. This is accomplished by a cartridge assembly wherein a cam member moves within an elongate guide path between two sets of staggered staple carrying grooves. Staple drive members are positioned in such a manner so as to be contacted by the longitudinally moving cam to effect ejection of the staples. The cartridge assemblies typically come in a plurality of sizes, each varying in both length and number of staples contained therein. Depending on the procedure to be performed, the surgeon must select the appropriate cartridge assembly.
The instruments described above were all designed for use in surgical procedures wherein surgeons have direct access to the operation site. However, in endoscopic or laparoscopic procedures, surgery is performed through a small incision or through narrow cannulae inserted through entrance wounds in the skin. In order to address the specific needs of endoscopic and/or laparoscopic surgical procedures, endoscopic surgical stapling devices such as those disclosed in U.S. Pat. No. B5,040,715 and U.S. Pat. No. 5,318,221, both to Green et al., have been developed. In general, these instruments are provided with clamping structure to effect approximation of an anvil and a staple cartridge to secure tissue therebetween, and staple firing structure to effect sequential ejection of a plurality of staples from the staple cartridge after the tissue has been secured.
Many of the instruments described above are limited in their range of operability. Improvements, however, have been made in the art of surgical instruments to provide increased range of operability. For example, U.S. Patent Nos. 5,312,023 and 5,326,013, both to Green et al., are directed to a surgical apparatus having a mechanism for effectuating the articulation of a fastener applying assembly disposed at a distal end of the instrument. The mechanism to effectuate articulation includes a rotatable dial member operatively associated with the exterior of the elongated tubular section and is connected to a cable loop or linkage which effects articulation. By turning the dial, the fastener applying assembly at the distal end of the instrument can be caused to articulate, i.e., bend away from the longitudinal axis of the instrument.
While the dial concept is useful, it would be helpful to provide the surgeon with an external articulation actuator mechanism that is movable in a manner that externally indicates the state of articulation of the fastening and cutting portion of the instrument relative to the elongated tubular shaft of the instrument. In laparoscopic procedures, such a mechanism would permit the surgeon to know the state of articulation without having to check video monitors. It would also be beneficial to provide an instrument including an actuation control member which is more readily and conveniently accessible to the user and which is easier to control during surgical procedures.